The whole sries looks fine to me:

Reviewed-by: Christoph Hellwig <hch@lst.de>

There are a few pieces of future work on top of this I'd rather see
sooner than later though:

 - use REQ_OP_FLUSH for all empty flushes, including those at the bio
   level.
 - merge the req->cmd_type values into req->op.  Right now that's
   basically only a new REQ_OP_BLOCK_PC (or better REQ_OP_SCSI while
   we're at it) and a REQ_OP_DRV_PRIV as the last value.
 - drop as many of the crazy defines based on REQ_* in fs.h (e.g.
   (READ_SYNC, WRITE_SYNC, WRITE_ODIRECT, WRITE_FLUSH, WRITE_FUA,
   WRITE_FLUSH_FUA, RW_MASK, RWA_MASK)